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Uncontrolled Resource ConsumptionWeakness · CWE-400

CVE-2026-44240

HIGH · 7.5 CVSS v3.1 Published 2026-05-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
basic-ftp is an FTP client for Node.js. Prior to 5.3.1, basic-ftp is vulnerable to client-side denial of service when parsing FTP control-channel multiline responses. A malicious or compromised FTP server can send an unterminated multiline response during the initial FTP banner phase, before authentication. The client keeps appending attacker-controlled data into FtpContext._partialResponse and repeatedly reparses the accumulated buffer without enforcing a maximum control response size. As a result, an application using basic-ftp can remain stuck in connect() while memory and CPU usage grow under attacker-controlled input. This can lead to process-level denial of service, container OOM kills, worker restarts, queue backlog, or service degradation in applications that automatically connect to FTP endpoints. This vulnerability is fixed in 5.3.1.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

basic-ftp prior to 5.3.1 is vulnerable to client-side DoS via unbounded memory accumulation when parsing FTP control-channel multiline responses. A malicious FTP server can send an unterminated multiline response during the initial banner phase, causing the client to continuously append data to FtpContext._partialResponse without size limits, leading to memory exhaustion and process-level denial of service.

MitigationUpgrade basic-ftp to version 5.3.1 or later which implements maximum control response size enforcement. Implement connection timeouts and memory monitoring as defense-in-depth measures.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify basic-ftp is installed
    Check your project's dependencies by reviewing package.json or running 'npm list basic-ftp' in the project root
    Affected if basic-ftp appears in dependencies or the npm list output shows the package
  2. Determine installed version
    Run 'npm list basic-ftp' or check the version field in node_modules/basic-ftp/package.json
    Affected if The version listed is earlier than 5.3.1 (for example, 5.3.0, 5.2.0, etc.)
  3. Confirm FTP client usage in your code
    Search your codebase for imports of basic-ftp (e.g., 'require("basic-ftp")' or 'import ... from "basic-ftp"') and look for FTP connection calls such as ftp.connect() or new FTPClient()
    Affected if Your application imports and uses basic-ftp to connect to remote FTP servers
  4. Check for custom response size limits
    Review your FTP client initialization code for any maxResponseSize, responseTimeout, or similar configuration options passed to the client
    Affected if No size limit or timeout is configured and the version is below 5.3.1

Your environment is affected if basic-ftp version is below 5.3.1 and your application uses it to connect to FTP servers without custom response size limits.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade basic-ftp to version 5.3.1 or later which implements maximum control response size enforcement. Implement connection timeouts and memory monitoring as defense-in-depth measures.

Recommended fix High confidence

basic-ftp version 5.3.1

  1. Identify the current version of basic-ftp in your project by checking package.json or running 'npm list basic-ftp'
  2. Upgrade basic-ftp to version 5.3.1 or later by running 'npm install basic-ftp@^5.3.1' or 'npm update basic-ftp'
  3. Verify the upgrade was successful by running 'npm list basic-ftp' to confirm version 5.3.1 or higher is installed
  4. Test your application to ensure the FTP functionality still works correctly after the upgrade

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-44240 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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